LASSA FEVER

Lassa fever is an acute viral hemorrhagic fever; just as Ebola, yellow fever and dengue are VHFs
Lassa fever was discovered in Lassa, Nigeria in 1969.
Lassa fever virus is a zoonotic illness, endemic in West Africa (Nigeria, Sierra Leone, Liberia, and Guinea).
Lassa fever virus resides naturally in the multimammate rat (Mastomys natalensis), but other species have to been known to host it. Mastomys rats are common in poor sanitary areas

Lassa fever epidemic occurs throughout the year, with peaks between November and May.

Lassa moves from rats to humans, when the latter is exposed to urine, saliva, blood or feces of the former. Transmission between humans occurs via contact with similar body fluids (or objects and surfaces contaminated with said fluids) and vomitus.

Lassa fever incubates inside an infected person for 3 – 21 days before symptoms appear.

80% of infections go unnoticed, as symptoms are mild and fleeting (fever, malaise, weakness, and headache)

20% of infections progress to muscle pain, sore throat, cough and chest pain, nausea and vomiting, abdominal pain and diarrhea, with severe cases progressing to hemorrhaging from gums, eyes or nose amongst other places with complications such as shock, hypotension.... DEATH usually follows within 2 weeks of symptoms, due to multi-organ failure.

General case mortality is less than 1%, while in-hospital case mortality is 15 – 20% (do not wonder why).

Neurological symptoms have also been described, including tremors, deafness and encephalitis.

Diagnosis is by ELISA to IgM, IgG antibodies and Lassa antigen, Reverse transcriptase PCR (in early stages); viral culture (takes 7 – 10 days)

Treatment – Ribavirin, when given early and supportive care concerning fluid and electrolyte balance, as well as treatment of supervening infections, if any.

PREVENTION and CONTROL

Community education on hygiene (prevent rodents being exposed to foodstuff), avoidance of contact with body fluids of sick people. Invaluable, also, is basic hand hygiene.

For health workers,

Practice standard precautions at all times (hand hygiene, correctly use PPE irrespective of provisional diagnosis)

Appropriately dispose and disinfect items used by Lassa fever patients

Clean hospital regularly using appropriate materials and methods.

Dispose all healthcare waste safely

Maintain a high index of suspicion for Lassa fever

Test all suspected malaria cases with RDT, if negative CONSIDER OTHER CAUSES OF FEVER INCLUDING LASSA FEVER

National guidelines for case management of Lassa fever is here http://ncdc.gov.ng/diseases/guidelines

Images from Google images